1. Field of the Invention
The present invention relates to auger type ice making machines, more particularly to an improvement of an extruding head assembly in the auger type ice making machines.
2. Description of the Prior Art
An auger type ice making machine of this kind incorporates an auger which is mounted for rotary movement within a cylindrical evaporator housing to which fresh water is supplied to cause ice crystals to form on the internal freezing surface of the evaporator housing. As the auger is driven by an electric motor drivingly connected to its lower end, the helical blade thereof scraps the ice crystals off the internal freezing surface of the evaporator housing and advances the scraped ice crystals upwardly toward an extruding head mounted on the upper end of the evaporator housing. The ice compressed at the extruding head is broken by a breaker blade and delivered as pieces of hard ice to an ice storage bin or a discharge duct mounted on the evaporator housing.
In general, the conventional extruding head is classified in first and second types as described below. In U.S. Pat. No. 4,741,173 issued on May 3, 1988, there is disclosed an extruding head of the first type which is formed with a plurality of straight ice extruding passages adapted to be positioned at the upper end of the evaporator housing for compressing the scraped ice crystals introduced therein under the action of the auger and for delivering the compressed ice bodies as relatively hard bodies of ice from its outlet. In U.S. Pat. No. 3,756,041 issued on Sep. 4, 1973, there is disclosed an extruding head of the second type which includes upper and lower head sections secured together and adapted to be positioned at the upper end of the evaporator housing. The lower head section is formed to define a cylindrical chamber therein for receiving the scraped ice crystals fed under the action of the auger and is provided with a plurality of radially extending extrusion passages in communication with the receiving chamber at their inner extremities. An extruding cam is disposed within the receiving chamber and mounted on the upper end portion of the auger for rotation therewith. The upper head section is formed with a plurality of radially extending depressions for deterring rotational movement of the scraped ice crystals within the receiving chamber. In operation, the scraped ice crystals from the evaporator housing are introduced into the receiving chamber under the action of the auger and forced radially outwardly by rotation of the extruding cam to be compressed at the extrusion passages.
In such extruding head assemblies as described above, the extrusion passages are tapered outwardly to compress the scraped ice crystals fed from the evaporation housing under the action of the auger. During compression of the ice crystals at the extrusion passages, the auger is applied with a great load caused by transfer resistances of the ice crystals at the extrusion passages. For this reason, the electric motor is designed, in general, to produce a large torque against the load acting on the auger. The electric motor, therefore, becomes large in size, resulting in consumption of the power.